Fix mattermost log location
Mattermost 3.8+ automatically appends mattermost.log to the location: https://github.com/mattermost/platform/commit/0b5c0794fdcbb551c1233dcdfbdf5c7deb585fd6
A change to make Mattermost backslash-agnostic is here: https://github.com/mattermost/platform/pull/7293
Closes #2718 (closed)
Edited by GitLab Release Tools Bot